def testadd(a:int,b:int)->int:
    pass

def testchar()->str:
    pass

def test_list(l:list):
    pass

def test_ret_list()->list:
    pass

def test_dict(d:dict):
    pass

def test_ret_dict()->dict:
    pass

def test_led_init():
    pass

def test_led(a:int):
    pass

def test_delay()->int:
    pass


"""
    callback 是一个函数，将它当作一个变量来做参数传递
"""
def test_event(self,callback:any):
    pass
